It has been demonstrated that effective toothbrushers exert a large amount of force against their teeth. On the other hand, ineffective toothbrushers exert far less force when they brush. In the past, poor toothbrushing habits often were attributed to poor brusher attitude; poor brushers commonly were assumed to be apathetic about their brushing habits. Howver, it is the belief of the applicant that many times poor toothbrushing results are caused by the application of inadequate force by the user against the teeth. Indeed, if the amount of force is corrected by instruction, the brusher will vastly improve the results of brushing.
Of necessity, instruction regarding the proper amount of force to apply during brushing must include a means for indicating to the user that a sufficient amount of force is in fact being applied to the teeth. An attempt at such an indicating means was made in Fugita U.S. Pat. No. 4,253,212, in which a force sensing device was located in the stem of a specially adapted toothbrush. The pressure sensing device was elastic, and when the stem bent under the force being applied to the teeth, the device detected the bending. An indicating device informed the brusher that an adequate amount of force was being used against the teeth.
Unfortunately, the Fugita device has two drawbacks. First, the stem must be custom made to include the sensing device. Thus, ordinary toothbrushes cannot be used with the Fugita device, increasing the expense and incovenience to the user. Second, the amount of pressure detected is not adjustable. As a result, the user cannot learn by gradually increasing the amount of force applied by a single toothbrush; rather he will be forced to apply the maximum preset amount of force to get feedback from the sensing device. Poor brushers might tire quickly or be unable to withstand the maximum exertion required of them at the start of the instructional program and give up using the device altogether.